1. Field
One or more aspects of embodiments according to the present invention relate to components of radio frequency systems with array antennas, and more particularly to a modular system for forming readily expandable array antenna systems.
2. Description of Related Art
Conventional active electronically scanned array (AESA) radar systems include arrays of antenna elements connected to a splitter-combiner network, which contains phase and amplitude control elements used for beam forming and beam steering. The splitter-combiner network may for example be configured as a corporate feed. The common input of the splitter-combiner network may be driven by a power amplifier, and the common output of the splitter-combiner network may be fed to a low-noise amplifier, for transmitted signals and received signals, respectively. The splitter and combiner networks may share certain components, such as phase control elements, which may be capable of use for both transmitted and received signals.
A structure of this sort is affected by what is known as the “N+1” problem, viz., the making of a small change in the requirements, such as increasing the number of antenna elements by one, necessitates a disproportionately large change in the design, such as the replacement of the splitter-combiner network. Thus, there is a need for an antenna array design which can be readily reconfigured to a larger or smaller number of elements or subarrays. Moreover, it is desirable that such a design be modular, allowing large or small collections of similar or identical elements to be assembled as needed, to form a large or small array.